As mature and development of electronic technology, hand-held terminals such as mobile phones become more and more popular, which brings great convenience for communication of people and meets the society requirements with fast pace and high-efficiency. In order to develop subscribers better, some mobile operators provide hand-held terminals for subscribers at low prices or for free, however, at the same time, the mobile operators require such hand-held terminals to bind themselves to networks of the mobile operators or lock themselves to Subscriber Identity Module (SIM) cards of the mobile operators, that is, so called network locking and card locking.
Generally, for hand-held terminals with network locking or card locking function, it is determined whether the current SIM card used by the hand-held terminal meets the requirement of network locking or card locking according to the International Mobile Subscriber Identity (IMSI) in the SIM card. Specifically, the basic principle of network locking or card locking is as follows: if the IMSI numbers meet the requirement of the mobile operator, the hand-held terminal is allowed to work normally; otherwise, the user is refused to use the hand-held terminal. Herein, there are total 15 numbers in the IMSI, the structure of which is MCC number+MNC number+MIN number, wherein there are 3 numbers for the Mobile Country Code (MCC); and there are 2 numbers for the Mobile Network Code (MNC).
However, at present, someone utilize the download channels of the hand-held terminals to illegally rewrite codes or date of the memories of the hand-held terminals, and to decode hand-held terminals to make the hand-held terminals lose network locking or card locking function, which makes mobile operators and hand-held terminal manufactures suffer huge losses. Therefore, it is required that hand-held terminals must be able to effectively prevent from being utilized to downloaded data illegally.
In the prior art, the download circuit of a hand-held device is generally as shown in FIG. 1, including: a first download connection point 102, a second download connection point 104 and a microprocessor 106; wherein the first download connection point 102 is connected with the microprocessor 106 through a wire, and the second download connection point 104 is connected with a battery cathode of the hand-held device. When it is required to download data, a data signal is loaded between the first download connection point 102 and the second download connection point 104, such that data is downloaded to the hand-held terminal. Generally, when the hand-held terminal user uses the hand-held terminal normally, it is unnecessary to download data for the hand-held terminal; therefore, the download circuit as shown in FIG. 1 has the following main defects: when no data needs to be downloaded by the hand-held terminal, the first download connection point 102 is still connected with the microprocessor 106, which may cause generation of illegal download.
In order to solve above technical problem, a technical solution is provided: a fuse module is added between the first download connection point and the microprocessor, when the hand-held terminal is outgoing from the factory, the fuse in the fuse module is fused, to achieve the purpose of disconnecting the download channel between the first download connection point and the microprocessor. FIG. 2 shows a diagram of fusing the fuse by introducing an additional download connection point, as shown in FIG. 2, a fuse module 208 is connected in series between the first download connection point 202 and the microprocessor 206, at the same time, a third download connection point 210 is introduced at one end where the fuse module 208 is connected with the microprocessor, the third download connection point 210 is used for providing a voltage required to fuse the fuse.
During process of producing a hand-held terminal by a manufacture, the fuse in the fuse module 208 is connected with the first download connection point 202 and the microprocessor 206, such that normal download can be executed, however, when the hand-held terminal is outgoing from the factory, a proper voltage is added between the first download connection point 202 and the third download connection point 210, in this case, current flows through the fuse to make the fuse fused, such that the purpose of disconnecting the download circuit is realized. However, this solution also has defect that, as the third download connection point 210 is still connected with the microprocessor 206 through the wire, it is possible to download illegal data for the hand-held terminal through the third download connection point 210.